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Traffic information services

Making your commute better

A circuitous path, involving England, New York, rural Michigan, Indiana, and lots of parts in between brought Matthew Freeman to Charlottesville, where he's been writing about mobile audio/video for Crutchfield off and on since early 2000. He fosters an eclectic taste in film, and is fond of a wide range of music. A native of Albuquerque, New Mexico, he found his way to the University of Notre Dame, where, in an act of charity unsurpassed in the history of Western civilization, he was given a B.A. in English.

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As people have gotten used to the idea of having a GPS navigation device telling them where to go, they've also discovered  the utility of using real-time traffic information services. These services, which work in a growing number of metropolitan and suburban areas, help keep you up-to-date on traffic conditions along routes you've programmed into your navigation system. They warn you of specific traffic incidents, including accidents and construction, which usually gives you time to adjust your route and avoid getting stuck in time-killing jams.

Traffic Information Services

How does it work?

Real-time traffic data is compiled by a traffic-information provider, then broadcast over a radio frequency to equipment set up to receive it. Depending on the equipment you have, you'll subscribe to a service that's broadcast over terrestrial FM, or to one that's broadcast along with satellite radio signals. Many new portable navigators now include this real-time traffic info for free. Traffic information doesn't interfere with FM or satellite radio reception, so you can continue to listen to either source while you receive traffic signals.

The traffic information comes from a variety of sources, including commercial traffic data providers, departments of transportation, police and emergency services, road sensors, traffic cameras, and even aircraft reports. This information is compiled and delivered via radio frequency (FM/HD Radio™ or satellite) to your navigation system. These providers work with the two main companies behind map data for the U.S., Tele Atlas and HERE (formerly known as NAVTEQ®), to deliver accurate representation of traffic data on GPS map displays.

Live traffic data on your GPS unit

Live traffic data warns you about delays on your route

In terrestrial FM applications, the traffic signals are broadcast over the FM Radio Data System (RDS), a special application of the radio band for sending small amounts of digital information. Most car stereos support FM RDS signals, which is how you can see radio station call letters or artist and song title information on your display when tuned to certain stations.

HD Radio signals broadcast traffic data in a similar fashion, but since HD Radio signals are able to carry more information, they can provide real-time updates more rapidly — up to four times more quickly than FM RDS in some cases. Traffic reports via HD Radio signals are not limited to in-dash receivers with HD Radio tuners — they can be received through some portable GPS systems as well.

To use the service, simply program a destination into your navigation system. As you drive, your system will receive and deliver alerts whenever a traffic incident comes up. You'll get both an audible warning and a visual indicator on the navigator's map, which shows you where along your route the incident has occurred. Many systems will automatically suggest alternate routes that enable you to steer you clear of the incident ahead.

Traffic incidents include accidents, emergencies, construction, scheduled road closures, and traffic diversions for occasions such as sporting events. Some services even offer detailed information about traffic flow and the average speed along your programmed route in certain high-traffic areas of select cities.

What are the benefits?

Your primary benefit is time. More often than not, you'll get warnings of traffic incidents along your route with time enough to avoid them. And since you're using the traffic data in conjunction with a navigation system, you'll get suggestions for the most efficient alternate routes. And that means less time spent sitting in gridlock.

Traffic-information services also let you get the most out of your navigation system. Normally, you wouldn't use a GPS unit to guide you to work, or to get you back home along familiar roads. But with real-time traffic info, you'll find that your navigation system becomes an invaluable traveling tool you'll use daily.

Traffic Information Services

Many portable navigation devices are compatible with live traffic information services

What do I need and how much does it cost?

Basically, all you need to enjoy real-time traffic information is a traffic-ready navigation unit and, usually, an antenna (satellite radio antennas can pick up traffic-information signals as well, if you're using a compatible satellite radio receiver). For most portable GPS navigators, the antenna is contained within a special power cable that comes with the device or can be bought separately. But not all navigators will show traffic reports even when connected to that type of cable — they also need to have compatible built-in software and a receiver to translate those signals.

As mentioned above, some newer portable GPS units and in-dash navigation receivers include either a limited or lifetime subscription to a traffic data service, typically for free and in some cases supported by on-screen advertising. Other devices or sources require a subscription to their service. Currently, the most popular traffic-information services are provided by:

  • Clear Channel's Traffic Message Channel — also known as Total Traffic & Weather Network (FM)
  • HERE/NAVTEQ Traffic RDS (FM)
  • SiriusXM satellite radio's NavTraffic (satellite)

Pricing depends on the source. For example, satellite radio subscription prices range from $3.99 per month (in addition to the regular satellite radio subscription) to $8.99 per month. Terrestrial FM services can cost up to $60 per year, but many manufacturers will offer a free trial of one or two years with purchase of their system.

What cities are covered?

Coverage currently includes many metropolitan areas. However, the number of cities covered has expanded quite a bit over the last few years. Rather than try to keep up with the list of cities, here are links to the coverage areas for the three providers listed above.

Total Traffic & Weather Network

HERE/NAVTEQ Traffic RDS and HERE/NAVTEQ Traffic HD Radio

SiriusXM satellite radio NavTraffic

App-based traffic services

As the in-dash receiver is seen more and more as an extension of the driver's phone or tablet, there has been a noticeable move toward incorporating specialized traffic apps, whether within the navigator or through a connected device. A couple of the more popular apps that are compatible with many in-dash touchscreen stereos are Waze and INRIX. Both apps rely on a combination of map-based traffic data and crowd-sourced reports from vehicles within nearby cellular networks to generate their traffic reports. These apps can be useful even in non-metropolitan areas where there isn't a dedicated traffic-info infrastructure, but they are heavily reliant on the ability to tap into cellular or even Wi-Fi® signals. If those signals are not present, the apps may be rendered next to useless. App compatibility varies depending on the stereo manufacturer, the phone, and operating system.

  • Joe Forbes from Virginia Beach

    Posted on 12/20/2015 6:59:27 PM

    very good article. However, I believe that you can subscribe to SiriusXM NAVTraffic service without adding an additional regular satellite radio subscription; at least this is what their customer service told me. I am debating on a SiriusXM subscription since I've about so many complaints regarding their service online.

  • Alexander Hrabe from Crutchfield

    Posted on 12/21/2015 6:21:44 AM

    Joe, according to SiriusXM's site, a minimum 1-year subscription is required if you do not subscribe to regular SiriusXM service.

  • Mike Spaulding

    Posted on 4/7/2017 5:19:42 PM

    Honestly, the traffic updates on Google Maps (which is free) are pretty dead-on. Waze even more so. I think it's unnecessary to buy a subscription service for this feature these days.

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